S&S Cycle Sidewinder 3 5⁄8 Big Bore Cylinders for Harley-Davidson Sportster Models—1986–2003 User Manual

Page 10

NOTE: All S&S® Sidewinder® kits have piston to piston clearance notch cut in the front skirt of rear piston. Rear piston must be installed with notch toward

the center of engine.

3. Install both cylinders and secure each with one head bolt.

4. Rotate flywheel until rods contact areas to be clearanced. Note angle that must be filed.

5. Disassemble cylinder and connecting rods and file crankcase and cylinder spigot for clearance. See Picture 12, below.

NOTE: A minimum of .060" clearance is required between connecting rods and crankcase and cylinder spigots.

6. Reassemble and check clearance.

7. Mark and grind other crankcase half to identical clearance.

B. Piston Clearance - Piston clearances must be checked to avoid piston to piston contact and piston to flywheel contact. See Pictures 13,

below left, and 14, below right.

NOTE: Pistons are normally clearanced in S&S kits, but good engine building practice demands that all clearances be checked during assembly. In the

event that additional clearancing must be done, weight of material removed from pistons generally is too small to significantly affect flywheel
balance.

1. Piston to Piston Clearance

a. Perform Steps 1 through 3 in Connecting Rod Clearance (Step A, page 9).

b. Rotate flywheel to position where pistons are closest to each other. This is at the bottom of the stroke. See Picture 13, above left.

c. Check clearance between pistons.

NOTE: A minimum of .060" clearance is required between piston skirts at the bottom of the stroke.

d. If clearance is not sufficient, disassemble cylinders and pistons, and carefully file notch in front skirt of rear piston until clearance is

obtained.

NOTE: The rear skirt of the piston is the primary thrust face, and carries the greatest load during engine operation. For this reason, piston to piston

clearancing is done on the front skirt of the rear piston in order to leave the rear skirts of both pistons as long as possible.

e. Reassemble and recheck clearance.

Picture 13

Picture 14

Picture 12